|Número de publicación||US4734742 A|
|Tipo de publicación||Concesión|
|Número de solicitud||US 06/933,663|
|Fecha de publicación||29 Mar 1988|
|Fecha de presentación||21 Nov 1986|
|Fecha de prioridad||21 Nov 1986|
|Número de publicación||06933663, 933663, US 4734742 A, US 4734742A, US-A-4734742, US4734742 A, US4734742A|
|Inventores||Robert C. Klumpp, Frederick B. Messbauer, Donald C. Buch|
|Cesionario original||Eastman Kodak Company|
|Exportar cita||BiBTeX, EndNote, RefMan|
|Citas de patentes (15), Otras citas (1), Citada por (17), Clasificaciones (40), Eventos legales (7)|
|Enlaces externos: USPTO, Cesión de USPTO, Espacenet|
This invention relates to optical scanners, and more specifically to a scanner capable of projecting images of opposite sides (duplex) of a document sheet onto electrooptical sensing means.
The output of optical scanners is used by a variety of types of devices, of which printers is only one. Although the problem giving rise to this invention is described in terms of a copier (a printer plus a scanner), the invention is usable in other applications of scanners as well.
Copiers presently on the market automatically expose opposite sides of a document by turning the document over between exposures at the same exposure station. The turnover mechanism is expensive, is a source of paper jams and can be the speed limiting aspect of an entire copying system.
U.S. Pat. Nos. 4,261,661, 4,247,192, and 3,980,406 show optical systems in which narrow line images of opposite sides of a moving document are sequentially projected onto moving light-sensitive material from exposure stations that are separate for the opposite sides. At least partially separate stationary optics are used for the respective stations, but document turnover or similar mechanisms are nevertheless employed. In several such systems a portion of the optical system is also movable for scanning a stationary object such as a book.
U.S. Pat. No. 3,936,171 shows a copier in which images of opposite sides of a document are projected virtually simultaneously using a straight through paper path. The images are projected by entirely separate optics onto separate photoconductive imaging drums. This system offers an increase in speed and a straight through paper path at the expense of an extra copying drum and accessories.
U.S. Pat. No. 3,885,871 shows an optical system for imaging opposite sides of serially fed documents onto film using two sets of mirrors and a single lens.
Optical exposing systems such as these are being replaced in copying by electrooptical scanning devices in which an electrooptical element having separately electronically addressable image sensing pixels, such as a linear CCD (charge-coupled device) receives a line scan of a document to create an electronic signal representative of the document. See, for example, U.S. Pat. No. 4,506,301. With such systems, ordinary duplex scanning would involve turning the document over between scans.
It is an object of this invention to provide a scanner of the type having a linear CCD or other similar electrooptical sensor which scanner is capable of scanning both sides of a given document without turning the document over.
This object is accomplished by a duplex scanner having means for directing scanning illumination along first and second optical paths from opposite sides of a document onto separate electrooptical sensors.
With separate sensors, both sides of the document can be scanned at the same time, greatly increasing speed as compared with consecutively scanning each side with the same sensor.
An advantage of scanning the opposite sides of the same document with at least partially separate optics is that the document does not have to be turned over. This eliminates the necessity of a costly turnover mechanism, reduces paper handling and paper jams. According to a preferred embodiment of the invention, the document is fed along a "straight through" paper path, with path lends itself to low cost and reliability.
According to another preferred embodiment of the invention, the optical system directs the images back through the same lens to the sensors, each located in an image plane of the lens. The advantage of using the same lens while doing such duplex scanning is that you save the substantial added expense of a separate lens for each side.
According to another preferred embodiment of the invention, the lens has an optical axis generally orthogonal to the direction of travel of the documents being scanned and lying in a plane generally parallel to the document itself. This construction lends itself to compactness and to a minimum of reflecting surfaces.
According to another preferred embodiment of the invention the second optical path, the lens and at least one sensor are movable for scanning a stationary object, for example, a book placed on an exposure platen.
According to another preferred embodiment of the invention a third electrooptical sensor is placed in the image plane of the lens and a third optical path is provided from a location on the path of movement of the document to that third sensor to monitor the orientation and thereby detect any skew in the document as fed. Such detection can be used to signal an operator or to actuate a mechanical mechanism for correcting for such skew.
FIGS. 1 and 2 are schematic front and side views respectively of a duplex scanner constructed according to the invention.
FIG. 3 is a schematic front view of another embodiment of the invention in which an optical system for scanning a stationary object such as a book is added to the duplex scanner shown in FIGS. 1 and 2.
According to FIGS. 1 and 2, a lens 1 has an image plane containing three electrooptical image sensors having separately electronically addresable pixels, for example, linear CCD's 2, 3 and 4. CCD 2 receives light directed from a first exposure station 25 along a first optical path 22 by mirrors 7 and 8. Exposure station 25 includes lamps 16 and 17 cooperating with reflectors 18 and 19.
CCD 4 receives light directed from a second exposure station 24 along a second optical path 21 by mirrors 5 and 11. Exposure station 24 includes lamps 14 and 15 cooperating with reflectors 12 and 13.
First and second exposure stations 25 and 24 are oriented so that images of opposite sides of a received document are projected at substantially the same time by lens 1 on CCD's 2 and 4. Optical paths 21 and 22 therefore project in generally opposite directions from the document and then are folded by mirrors 5, 7, 8 and 11 back through lens 1.
CCD 3 receives light along a light path 23 directed by mirros 6, 9 and 10 from a position 30 near exposure stations 25 and 24 through the lens 1.
In operation a document is fed along a document path 20 by rollers 26, 27, 28 and 29 past position 30 and exposure stations 24 and 25. As the document passes exposure station 25, an image of the bottom side of the moving document is projected onto CCD 2. As the document passes exposure station 24, an image of the top side of the document is projected onto CCD 4. As the document passes point 30, the orientation of the front edge of the document is sensed by CCD 3. The mirrors are arranged so that all the light paths are directed through lens 1 with lens 1 oriented with its optical axis substantially orthogonal to the direction of motion of the document and lying in a plane roughly parallel to the document itself. This provides a very compact arrangement for scanning both sides of the document at substantially the same time with a minimum of reflecting surfaces, and with substantial cost savings associated with using the same lens.
The use of separate sensors 2 and 4 allows both sides of the document to be scanned at the same time. This essentially doubles the output of an ordinary scanner which would scan the two sides consecutively onto the same sensor, even assuming any document turn around time can be eliminated in the latter structure. The output of the sensors are electronic signals which can be fed into separate memories and read out by a printer, a facsimile apparatus, a computer terminal or the like. If both the scanner and, for example, a printer are executing the same job at the same time, using a one page buffer, the printer can operate at twice the speed of the document feed portion of the scanner.
Thus, this scanner at least doubles the speed of an ordinary scanner at the cost of several reflecting surfaces and an extra linear CCD. The cost of the latter has become a small fraction of its cost a few years ago.
This structure also has the advantages associated with a straight through paper path of greatly reducing the problems associated with paper jams and the expense associated with turnover mechanisms and the like. Thus, the invention provides increased reliability as well as reduction in parts.
FIG. 3 shows the same optical system as FIGS. 1 and 2 with the added feature that mirrors 6, 7, 8, 9 and 10, lens 1, illumination lamps 16 and 17, reflectors 18 and 19 and CCD's 2, 3 and 4 are all movable together to scan a stationary document or object, for example, a book placed on an exposure platen 31.
In the FIG. 3 embodiment, the elements defining optical path 23 are also movable, reading the first edge encountered in the scanning process, the right edge of the book shown in FIG. 3.
The location of the lens in a direction orthogonal to the direction of movement of the document again allows easy access to light paths from opposite sides of the document while providing clearance between the document and those optical paths. In the FIG. 3 embodiment, this lens orientation permits movement of a portion of that optical system without also interfering with the stationary document.
CCD 3 senses the skew of the document in both the FIGS. 1 and 2 embodiment and the FIG. 3 embodiment. In the FIGS. 1 and 2 embodiment this can be used to mechanically correct for such skew as is well known in the art, see, for example, U.S. Pat. No. 4,310,236. In both embodiments the output of CCD 3 can be used to electronically correct for the skew by electronically rotating the document by the use of appropriate logic, see, for example, U.S. Pat. No. 4,558,461. The output of CCD 3 can also be used to signal the operator that there is a skew in the document.
The invention has been described in detail with particular reference to a preferred embodiment thereof, but it will be understood that variations and modifications can be effected within the spirit and scope of the invention as described hereinabove and as defined in the appended claims.
|Patente citada||Fecha de presentación||Fecha de publicación||Solicitante||Título|
|US3637302 *||19 Jul 1968||25 Ene 1972||Pelorex Corp||Compact copying machine with multiple-function reciprocating carriage|
|US3885871 *||12 Abr 1974||27 May 1975||Ibm||Document photography system|
|US3936171 *||11 Mar 1974||3 Feb 1976||Xerox Corporation||Electrostatographic methods and apparatus|
|US3980406 *||2 Jun 1975||14 Sep 1976||Xerox Corporation||Duplex imaging system|
|US3981580 *||5 Nov 1974||21 Sep 1976||Ricoh Co., Ltd.||Method and a system for concurrently copying both sides of an original|
|US4110030 *||14 May 1976||29 Ago 1978||Canon Kabushiki Kaisha||Electrostatic copying apparatus|
|US4247192 *||23 Oct 1978||27 Ene 1981||Canon Kabushiki Kaisha||Copying machine|
|US4261661 *||6 Abr 1979||14 Abr 1981||Agfa-Gevaert N.V.||Apparatus for producing double sided copies|
|US4506301 *||12 Oct 1979||19 Mar 1985||Xerox Corporation||Multiple mode raster scanner|
|US4571636 *||21 Dic 1983||18 Feb 1986||Fuji Xerox Co., Ltd.||Device for reading images of both surfaces of an original in one pass|
|US4616269 *||23 Sep 1985||7 Oct 1986||Fuji Xerox Co., Ltd.||Document reader|
|US4673285 *||23 May 1986||16 Jun 1987||Xerox Corporation||Optical scanning of duplex documents|
|JPS6070436A *||Título no disponible|
|JPS55153964A *||Título no disponible|
|JPS59123833A *||Título no disponible|
|Patente citante||Fecha de presentación||Fecha de publicación||Solicitante||Título|
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|US5280321 *||8 Sep 1992||18 Ene 1994||Eastman Kodak Company||Dual roll rotary microfilmer for 25x reduction or less|
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|US5488485 *||3 Abr 1995||30 Ene 1996||Canon Kabushiki Kaisha||Image reading apparatus|
|US5610682 *||3 Ene 1995||11 Mar 1997||Hirakawa Kogyo Sha Co., Ltd.||Photographing method and photosensitive material printing apparatus utilizing the same|
|US5646744 *||11 Ene 1996||8 Jul 1997||Xerox Corporation||Show-through correction for two-sided documents|
|US5828469 *||21 Mar 1997||27 Oct 1998||Xerox Corporation||Document scanner with gravitational registration|
|US6101283 *||24 Jun 1998||8 Ago 2000||Xerox Corporation||Show-through correction for two-sided, multi-page documents|
|US6942213 *||26 Mar 2003||13 Sep 2005||Seiko Epson Corporation||Duplex scanning device|
|US7965421||16 Abr 2008||21 Jun 2011||Xerox Corporation||Show-through reduction method and system|
|CN102098415B||14 Dic 2010||30 Jul 2014||佳能株式会社||Image reading device and method of controlling the image reading device|
|EP0570958A1 *||19 May 1993||24 Nov 1993||Sharp Kabushiki Kaisha||A reflective and transmissive original pickup apparatus and a method of reading the original|
|EP0678787A1 *||12 Oct 1994||25 Oct 1995||Hirakawa Kogyo Sha Co., Ltd.||Photographing method, and photosensitive material printing apparatus utilizing the same|
|EP0784396A2||31 Dic 1996||16 Jul 1997||Xerox Corporation||Show-through correction for two-sided documents|
|EP2337332A3 *||13 Dic 2010||1 Ago 2012||Canon Kabushiki Kaisha||Image reading device for correcting image read from original, method of controlling the image reading device, and storage medium|
|Clasificación de EE.UU.||355/23|
|Clasificación internacional||H04N1/193, H04N1/12, H04N1/00, H04N1/10, G03G15/23, G03B27/52, H04N1/107, G03G15/04, G03B27/48, H04N1/203|
|Clasificación cooperativa||H04N1/2032, G03G15/0435, H04N1/193, G03G15/04, H04N1/00681, H04N1/12, H04N1/00734, H04N1/0057, G03B27/528, G03G15/23, H04N1/00745, H04N1/203, G03B27/48, H04N1/00718, H04N1/00787, H04N1/0075|
|Clasificación europea||H04N1/00G4D, H04N1/00G3C, H04N1/00G4B, H04N1/203P, H04N1/00G2E, H04N1/00G6B, G03B27/52P2S, G03B27/48, H04N1/00G, H04N1/00F2, H04N1/203, G03G15/04, G03G15/23|
|11 Ene 1988||AS||Assignment|
Owner name: EASTMAN KODAK COMPANY, ROCHESTER, NY A CORP. OF NJ
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNORS:KLUMPP, ROBERT C.;MESSBAUER, FREDERICK B.;BUCH, DONALD C.;REEL/FRAME:004839/0358;SIGNING DATES FROM 19861111 TO 19861114
Owner name: EASTMAN KODAK COMPANY, A CORP. OF NJ,NEW YORK
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:KLUMPP, ROBERT C.;MESSBAUER, FREDERICK B.;BUCH, DONALD C.;SIGNING DATES FROM 19861111 TO 19861114;REEL/FRAME:004839/0358
|11 Ene 1988||AS02||Assignment of assignor's interest|
|22 Jul 1991||FPAY||Fee payment|
Year of fee payment: 4
|17 Jul 1995||FPAY||Fee payment|
Year of fee payment: 8
|30 Ago 1999||FPAY||Fee payment|
Year of fee payment: 12
|19 Jun 2001||AS||Assignment|
|15 Oct 2004||AS||Assignment|
Owner name: EASTMAN KODAK COMPANY, NEW YORK
Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:NEXPRESS SOLUTIONS, INC. (FORMERLY NEXPRESS SOLUTIONS LLC);REEL/FRAME:015928/0176
Effective date: 20040909